US3272169A - Passive ship stabilizer using terminal damping means - Google Patents

Passive ship stabilizer using terminal damping means Download PDF

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Publication number
US3272169A
US3272169A US386198A US38619864A US3272169A US 3272169 A US3272169 A US 3272169A US 386198 A US386198 A US 386198A US 38619864 A US38619864 A US 38619864A US 3272169 A US3272169 A US 3272169A
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US
United States
Prior art keywords
tank
ship
pipes
liquid
stabilizer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US386198A
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English (en)
Inventor
Lawrence W Ward
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
John J Mcmullen Associates Inc
Original Assignee
John J Mcmullen Associates Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US386198A priority Critical patent/US3272169A/en
Application filed by John J Mcmullen Associates Inc filed Critical John J Mcmullen Associates Inc
Priority to DEP1270A priority patent/DE1270980B/de
Priority to NL6509886A priority patent/NL6509886A/xx
Priority to DK393265AA priority patent/DK119867B/da
Priority to GB32807/65A priority patent/GB1096472A/en
Priority to NO159143A priority patent/NO122823B/no
Priority to FI1843/65A priority patent/FI43688B/fi
Priority to SE10018/65A priority patent/SE339182B/xx
Priority to FI1761/66A priority patent/FI43692B/fi
Application granted granted Critical
Publication of US3272169A publication Critical patent/US3272169A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
    • B63B39/02—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by displacement of masses
    • B63B39/03—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by displacement of masses by transferring liquids

Definitions

  • This invention relates to a passive ship stabilization system and more particularly a passive ship stabilization system using energy dissipating means mounted at the center and terminal ends of said system for damping the kinetic energy of moving fluid therein.
  • FIG. 1 is a schematic representation of a hull of a water going vessel showing one possible location of the passive ship stabilizer mounted therein;
  • FIG. 2 is a top plan view of one embodiment of the present invention with the top of the tank removed for the purpose of clarity;
  • FIG. 3 is a sectional view taken along line 33 of FIG. 2;
  • FIG. 4 is a top plan view of another embodiment of the present invention.
  • FIG. 5 is a sectional view taken along line 55 of FIG. 4;
  • FIG. 6 is a top plan view of still another embodiment of the present invention.
  • FIG. 7 is a sectional view taken along line 7--7 of FIG. 6.
  • FIG. 1 of the drawings there is illustrated a ships hull 10 with a passive stabilization system generally indicated as 12 mounted between two decks thereof.
  • the stabilization system can comprise a plurality of side plates and end plates mounted or welded between two existing decks of the ship 10 so that the upper deck will act as a top and the lower deck will act as a bottom for the passive stabilization system.
  • a body of liquid is disposed throughout said stabilization system or liquid storage tank 12, and said body of liquid transfers from one end of said tank 12 to the other in response to the roll of the ship.
  • the geometry of the tank and the liquid mass are such that the natural period of the tank liquid is tuned to the natural period of roll of the ship and 90 out of phase so that the proper stabilizing moment can be imparted to the ship.
  • Tank 12 is comprised of two side plates 14 and 16 and two end plates 18 and 20.
  • the tank has a longitudinal axis which is disposed substantially athwartship as can be seen in FIG. 1 and has a longitudinal dimension substantially greater than any lateral dimension thereof.
  • a plurality of small diametered pipes 22 are mounted in the respective side plates 14 and 16 and extend laterally and horizontally across one end of tank 12.
  • the outer surfaces of at least some of the pipes 22 are continuous about each respective axis thereof and are spaced from all other structures in the tank.
  • the disposition of said pipes 22 is such as to form a substantially V-shaped configuration in cross section or profile.
  • a similar set of pipes 24 is horizontally mounted at the other end of said tank 12 and is also spaced vertically and diagonally with respect to each other to form a V- shaped configuration when viewed in section.
  • Another plurality of pipes 26 are mounted from the top to bottom at the center of tank 12 and form three staggered rows disposed laterally across tank 12.
  • the diameters of pipes 22, 24 and 26 are small and do not choke off or greatly throttle the transfer of liquid passing therebetween.
  • the velocity of transferring fluid is not greatly reduced but yet a substantial amount of kinetic energy is dissipated due to the scrubbing or friction imparted to the transferring fluid by the stationary pipes.
  • This phenomenon can be accounted for by recognizing the fact that energy damping is proportional to the square of the velocity of the transferring fluid.
  • substantially no local potential head is created. Therefore, the fluid motion impedance provided by pipes 26 at the center of said tank 12 is enhanced by the screen effect, friction, and tortuous flow caused by their particular arrangement.
  • the V-shaped profile for the disposition of pipes 22 and 24 functions to dampen energy of the horizontal component of moving liquid at the ends of the tank 12 as well as the vertical component of moving liquid thereat. Therefore, this design is particularly good for ships which can anticipate experiencing great degrees of roll.
  • the fiuid to be employed within the stabilizer can be any liquid or the like having sufficient density and with a viscosity of a sufliciently low magnitude so that flow can readily take place between pipes 26 and pipes 22 and 24.
  • Liquids such as sea water, fresh water, bunker oil or types of liquid cargo can be used in the stabilizer tank.
  • Vertical pipes 26 also function to prevent great surges of fluid transfer in response to violent rolling of the ship and to dissipate energy of transferring liquid. If desired, pipes 22 and 24 can be disposed entirely below the static surface level of the fluid within tank 12 without departing from the spirit of the present invention.
  • the fluid mass at the left side of tank 12 is given a greater potential energy so that a hydrostatic head is formed thereat.
  • the fluid mass then begins to transfer toward the right side of tank 12, again passing through pipes 26 which dissipates substantial amounts of energy, but does not greatly reduce the velocity of transferring fluid, and said fiuid mass accumulates at the right side of tank 12.
  • the accumulation of said fluid mass again rises vertically through pipes 24, 22 and a substantial amount of kinetic energy is dissipated thereby.
  • the right side of ship 10 has gone through its lowermost position and returned to the horizontal and begins to rise, the rising thereof being opposed by the great mass of fluid at the right side of tank 12.
  • stabilization forces are imparted to the ship in opposition to the roll thereof.
  • the energy and external forces imparted to the ship by the sea are dissipated and sufiiciently controlled by the kinetic energy damping means, which in this case comprises vertical pipes 26 and horizontally arranged pipes 22 and 24. Therefore, the roll of the ship is in balance with the natural period of the passive stabilizer and the external energy imparted to the ship is dissipated by said stabilizer.
  • FIGS. 4 and 5 there is illustrated a liquid storage means 12 again having a body of the liquid therein.
  • Two staggered rows of three horizontally disposed pipes 28 are mounted in the sides of said container 10, said pipes also having a small diameter and disposed beneath the static surface level of the body of fluid.
  • the pipes 28 are disposed in two staggered rows if desired, their arrangement may be even.
  • the operation of the system shown in FIGS. 4 and 5 is substantially the same as that shown in FIGS. 2 and 3.
  • FIGS. 6 and 7 there is shown an elongated tank 12 having two rows of vertically disposed and staggered pipes 30 arranged laterally across the center thereof. If desired, more than two rows of pipes 30 can be mounted within tank 12, depending upon the anticipated rolling characteristics of the ship.
  • Two horizontally disposed pipes 32 and 34 mounted transversely across said tank 12 are mounted in the sides thereof.
  • the horizontal pipes 32 and 34 are used to support respective pluralities of horizontal pipes 36 and 38, each of which have one end mounted to pipes 32 and 34, respectively, and the other end thereof mounted in the respective end plates of the tank 12. Therefore, the pipe arrangements 32, 36 and 34, 38 form a pair of ladder configurations mounted at respective ends of tank stabilizer 12.
  • the plane of the ladder is disposed in a horizontal plane or a plane parallel to the horizontal surfaces of tank 12.
  • a body of liquid is disposed in tank 12 and has a static liquid surface just above the vertical location of the ladder arrangements 32, 36 and 34, 38.
  • FIGS. 6 and 7 The operation of the embodiment shown in FIGS. 6 and 7 is substantially the same as that described above.
  • the moving liquid mass arrives at either end of tank stabilizer 12, it assumes a vertical direction and the horizontally disposed ladder arrangements 32, 36 and 34, 38 impart a resistance to the vertically moving fluid therethrough.
  • a ship stabilizer comprising an elongated tank mounted in a ship with its long axis transverse to the roll axis of the ship, a liquid body partially filling said tank, a plurality of elongated members mounted in said tank at each of the longitudinal end regions thereof, each of said plurality of members being arranged in a substantially horizontal plane, a portion of the outer surface of each of said members being continuous around the axis thereof and being spaced from the sides and ends of said tank and from the others of said plurality of members, whereby a portion of said liquid body transfers in said tank and passes upwardly through the spaces between said members in response to the roll of said ship.
  • a stabilizer set forth in claim 2 wherein a plurality of vertically extending members are mounted on the bottom of said tank in the central portion thereof, said vertical members being generally aligned across the center portion of said tank.
  • each said member has a small cross sectional area so that the plurality of members as a group imparts substantially no back pressure head to the transferring liquid.
  • each said pipe has a small cross sectional area so that the vertical and horizontal pipes impart substantially no bacfpressure head to the transferring liquid.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Vibration Prevention Devices (AREA)
US386198A 1964-07-30 1964-07-30 Passive ship stabilizer using terminal damping means Expired - Lifetime US3272169A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US386198A US3272169A (en) 1964-07-30 1964-07-30 Passive ship stabilizer using terminal damping means
NL6509886A NL6509886A (de) 1964-07-30 1965-07-30
DK393265AA DK119867B (da) 1964-07-30 1965-07-30 Søgående fartøj med et passivt stabiliseringsanlæg.
GB32807/65A GB1096472A (en) 1964-07-30 1965-07-30 Passive-tank ship stabilizer using terminal damping means
DEP1270A DE1270980B (de) 1964-07-30 1965-07-30 Passiver Tankstabilisator fuer Schiffe
NO159143A NO122823B (de) 1964-07-30 1965-07-30
FI1843/65A FI43688B (de) 1964-07-30 1965-07-30
SE10018/65A SE339182B (de) 1964-07-30 1965-07-30
FI1761/66A FI43692B (de) 1964-07-30 1966-06-30

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US386198A US3272169A (en) 1964-07-30 1964-07-30 Passive ship stabilizer using terminal damping means

Publications (1)

Publication Number Publication Date
US3272169A true US3272169A (en) 1966-09-13

Family

ID=23524582

Family Applications (1)

Application Number Title Priority Date Filing Date
US386198A Expired - Lifetime US3272169A (en) 1964-07-30 1964-07-30 Passive ship stabilizer using terminal damping means

Country Status (8)

Country Link
US (1) US3272169A (de)
DE (1) DE1270980B (de)
DK (1) DK119867B (de)
FI (2) FI43688B (de)
GB (1) GB1096472A (de)
NL (1) NL6509886A (de)
NO (1) NO122823B (de)
SE (1) SE339182B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3951089A (en) * 1973-05-04 1976-04-20 Hydroconic Limited Roll-damping tanks for waterborne vessels

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3083674A (en) * 1961-10-13 1963-04-02 Mcmullen Ass John J Linear-response flume stabilizer
US3083673A (en) * 1960-10-25 1963-04-02 Mcmullen Ass John J Passive stabilization system

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3054373A (en) * 1960-02-16 1962-09-18 Mcmullen Ass John J Flume type heeling tank stabilizer

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3083673A (en) * 1960-10-25 1963-04-02 Mcmullen Ass John J Passive stabilization system
US3083674A (en) * 1961-10-13 1963-04-02 Mcmullen Ass John J Linear-response flume stabilizer

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3951089A (en) * 1973-05-04 1976-04-20 Hydroconic Limited Roll-damping tanks for waterborne vessels

Also Published As

Publication number Publication date
FI43688B (de) 1971-02-01
FI43692B (de) 1971-02-01
DK119867B (da) 1971-03-01
DE1270980B (de) 1968-06-20
SE339182B (de) 1971-09-27
NO122823B (de) 1971-08-16
NL6509886A (de) 1966-01-31
GB1096472A (en) 1967-12-29

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